多项选择题
A. INSERT INTO employees VALUES ( NULL, ‘John’,‘Smith’);
B. INSERT INTO employees( first_name, last_name) VALUES(‘John’,‘Smith’);
C. INSERT INTO employees VALUES (‘1000’,‘John’,NULL);
D. INSERT INTO employees(first_name,last_name, employee_id) VALUES ( 1000, ‘John’,‘Smith’);
E. INSERT INTO employees (employee_id) VALUES (1000);
F. INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, ‘John’,‘’);
单项选择题 The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER(4) NOT NULL CUSTOMER_NAME VARCHAR2(100) NOT NULL STREET_ADDRESS VARCHAR2(150) CITY_ADDRESS VARCHAR2(50) STATE_ADDRESS VARCHAR2(50) PROVINCE_ADDRESS VARCHAR2(50) COUNTRY_ADDRESS VARCHAR2(50) POSTAL_CODE VARCHAR2(12) CUSTOMER_PHONE VARCHAR2(20) A promotional sale is being advertised to the customers in France. Which WHERE clause identifies customers that are located in France?（）
单项选择题 In which scenario would an index be most useful?（）
单项选择题 What is true regarding subqueries?（）